Hello all,
I need some help accomplishing the following: I need a circuit that goes from the 5v PWM pins on the arduino mega to a meanwell ELN-P. I need to control 8 seperate meanwells.
I am assuming that I would need to use 8 different PWM pins on the mega, right?
A friend from a reefing forum shared his Eagle file, but I do not have a BOM and quite frankly don't understand the schematic.
Does anyone have layman's termed solution for this circuit?
Thank you so much for your help!
From what I could see from the spec here:
http://www.meanwell.com/search/eln-60/eln-60-spec.pdf
(not sure if you have the 60 - but its probably similar), you need a PWM signal of 10V; the Arduino's 5V output may or may not work. If you wish to control 8 of them, you can use 8 lines (probably easiest), or you can use another solution (like a shift register). Since you have a mega, though, using 8 lines would be simpler.
Probably the simplest way to set this up would be to use those 8 lines to drive 8 smallish NPN transistors (or n-channel mosfets) to switch the 10V. The basic circuit would look similar to a relay or solenoid driver (one on each pin), minus the relay/solenoid (and snubber diode):
Basically, you would insert the Meanwell PWM pins in where the relay/solenoid would go, positive lead to the 10VDC positive supply, and the negative lead to the collector/drain of the transistor/mosfet.
Simple level conversion, really. You could possibly also use a NPN darlington array chip as a driver, too (like a ULN2003), instead of individual transistors...
Would this also work?
http://forum.allaboutcircuits.com/attachment.php?attachmentid=17034&d=1268088159
If you're referring to the ELN shield from DWIZUM on Reef Central, then the man is an outright genius. Just contact him and he'll get you set on the right path.
(I keed, I keed!)
I was just in the middle of a PM to you over on RC explaining the shield's operation. But for the record, the ELN-P will NOT work directly on a 5v signal from the Arduino. There are rumors that the p-type and d-type are essentially one in the same - if you supply 5v to the p-type, it only turns on about halfway. cr0sh's explanation is basically what the ELN shield does. It uses an NPN transistor to switch 10v to each of the ELNs. A PWM pin on the Arduino switches the NPN on and off. It's basically multiples of the relay schematic he linked, with a few small tweaks. I've made both "plain" and "Mega" versions of the shield. Here's a slightly outdated version of the schematic for the plain version, but it gets the point across:
Would this also work?
That's my schematic that someone's posted on another forum, apparently with a 10k pulldown drawn on one of the pins. The pulldown isn't required (and I'm not quite sure that's where you'd want it if you did want to add one) - when the ELN sees a floating input, it goes straight to zero. So, switching the signal between 10v and floating is perfectly fine.
